This invention pertains to an anti-puncture (as by a bullet wound), self-sealing, water-leak-inhibiting, coating, or coating structure, preferably sprayed into place on a boat hull (also referred to herein as the hull of a water vessel), and deployed, selectively, on either an outside surface area only, an inside surface area only, or on both outside and inside surface areas, of such a hull. In the present description of the invention, the term “hull” herein is intended to refer not only what is classically recognized to be that portion of a boat which directly engages a supporting body of water, but also any relevant, and user-selectable, internal bulkhead, such as a bilge bulkhead, or the like, which might be exposed to a water-leak-risk puncture wound.
The self-sealing coating of the present invention, which is also referred to herein generally as a water-leak-inhibiting, spray-applied protection structure for various, herein-named portions of a boat hull, specially employs seal-enhancing, water-reactive material, and offers a number of important, interesting and extremely useful advantages with respect to inhibiting water-leakage. One of these interesting advantages, as will be seen, is that the pressure of water itself, on the “leakage-in” side of a leak, plays a contributing role in sealing a puncture leak. So, in two important ways, the very water medium against which leakage protection is provided by the invention is centrally enrolled in the intended anti-leak behavior of the invention.
By way of generally related background information, reference is here made to U.S. Pat. No. 7,169,452 B1, in which patent, there is described and illustrated a self-healing coating applied to the outside of a liquid, petrochemical fuel container to seal an “inside-to-outside” fuel leak caused by a projectile puncture wound. In that patent, the illustrated and described coating is formed with plural layers, including a pair of bracketing, “outer” layers which are formed of a fuel-reactive, high-elastomeric material, and sandwiched-between these two outer layers, an intermediate layer formed with a body of essentially the same, just-mentioned, high-elastomeric material and further including an entrained population of fuel-reactive, solid-polymer, liquid-imbiber beads. The entirety (all layers included) of the high-elastomeric material which is employed in the coating structure of the invention forms what is referred to herein as a continuous-phase body of material.
With respect to this prior art patented structure, while it is generally related in a background sense to the present invention, it is important to note that all of the fuel-reactive materials which make up the illustrated coating, prior to any puncture leak occurring, are initially, and normally, completely out of contact with the liquid fuel regarding which they are intended to react to assist in sealing that leak. This condition, as it will be seen, describes one of several important differences that distinguish the technology content of this background patent from that of the present invention.
More particularly, in the present context of protecting a boat hull against a water leak produced by a similar kind of puncture wound, and recognizing that the coating structure of the invention employs, as mentioned above, a specially included, water-reactive sealing material, it is important to recognize that this coating structure, particularly when it is applied to and on the outside of a hull, though it can be true also with respect to coating material applied to and on the inside of a hull, such as within the bilge area of a hull, will be, either continuously, or frequently, directly in contact with water—the very liquid with respect to which a reaction will “ultimately” be produced, in accordance with operation of the present invention, to assist in a sealing action if and when a puncture wound occurs. Obviously, such a coating structure, though it must reside normally within a contacting water environment, must not be one in which the very material content therein which is intended to react to leaking water is subjected, initially and nominally, to direct exposure to water, with respect to which “unwanted exposure” the coating would most certainly “pre-spend” itself before any actual water-leakage occurs.
Accordingly, the coating (coating structure) proposed by the present invention includes a body of continuous-phase, non-water-reactive, high-elastomeric-material, and embedded within that body, in an initially shrouded and non-exposed condition guarded nominally against any contact with external water, a distribution of water-reactive, water-imbiber beads. In a more particular sense, the invention coating takes the form of a plural-layer construction which features (a) a pair of spaced layers, referred to as inner and outer layers, that are made solely of a suitable, non-water-reactive, high-elastomeric material, and (b) a special, intermediate layer which is formed with a body of similar high-elastomeric material containing the mentioned embedded, and initially and nominally “shrouded/guarded” (against initial, non-puncture water contact) population of liquid(water)-imbiber beads which are reactive specifically to water. These imbiber beads furnish the only material in the entire proposed coating structure which reacts (with a swelling/congealing response) to contact with water.
With respect to this coating, the employed high-elastomeric material plays an important response role, but not a material-reactive/water-reactive response role, when a puncture wound occurs. Material reaction to contact with water, which kind of reaction does definitively occur ultimately in the invention's rapid and effective response to a through-puncture wound, does not occur until after an actual, “through-puncture” water leak occurs, which leak exposes, to direct contact with water, the centrally embedded water-imbiber beads. These beads, on such contact, react with swelling and congealing actions, and through such actions respond rapidly, in cooperation with adjacent high-elastomeric-material, tension-based, compressive behavior, to seal a water-leak puncture wound.
While different high-elastomer materials may be employed in the coating structure of the present invention, one high-elastomeric product/system material, a preferred material, which has been found to be extremely effective is sold under the trademark LINE-X® protective coating, a polyurea, high-elastomer material made by Advanced Protective Coatings, dba LINE-X, a company based in Huntsville, Ala. Another very suitable high-elastomer material is a two-component, polyurethane product made by Rhino Linings, USA, a company based in San Diego, Calif., sold by that company under the trademark TUFF STUFF®. The mentioned water-imbiber beads preferably take the form of the solid-phase, polymer-bead product sold under the trademark AQUA BIBER®, made by Imbibitive Technologies America, Inc. in Midland, Mich.
Where one chooses to employ principally, rather than the LINE-X® product, the TUFF STUFF® product as the principal, high-elastomeric material in a coating made in accordance with the present invention, then, on the outside of a boat hull, it may be desirable to use also the somewhat higher-durometer, above-mentioned LINE-X® polyurea product either as an additional, exposed, outer layer applied to a TUFF STUFF® nominal water-exposed outer layer, or to use the mentioned LINE-X® product to form the entirety of a water-exposed outer layer. Such a higher-durometer outer layer, as an option, has the advantage of furnishing better abrasion resistance regarding accidental “hull contact” with some outside foreign structure.
All of the herein mentioned high-elastomeric products are compatible with, and bond well to, one another, and as a consequence form, in a finished coating structure, a continuous-phase, body of non-water-reactive, elastomeric material.
The proposed coating is preferably one which, (a) is, as mentioned above, spray applied to the locations where it is used, (b) is a multi-layer structure, (c) adds relatively little to the overall weight of a boat, and (d), with respect to where it is applied to water-contact areas on the outside of a boat hull, furnishes a very smooth-surfaced outside “finish” which does not inhibit efficient boat-hull travel through the water. Uniquely, the protection coating of the present invention: (1) is highly elastomeric in nature (a condition—referred to with the term “high-elastomeric” which we apply to the high elastomericity of the chosen, preferred and above-mentioned high-elastomeric materials—well over 200% reversible stretch capability—a condition which is important for reasons which will become apparent as further description of the invention follows below: and (2), enhanced by including an initially nonexposed, internally embedded (about 22% by volume) population of water-imbiber beads which react to puncture/penetration-event contact with water to function with an aggressive swelling and congealing action which responds very rapidly to such water exposure.
Interestingly, and as has been mentioned, the protective coating of this invention is, and this is certainly nearly always true on the outside of a boat hull, constantly exposed to the very substance—water—with respect to which it's embedded imbiber beads are intended to react with a swelling and sealing action. But, this coating must not react to water until there is a puncture event.
Another important and interesting feature of the invention, worth stressing again here, is that, with respect to coating structure applied to the outside of the hull, or applied anywhere that “outside”, contacting water bears against that structure, on the occurrence of a puncture wound, and of resulting exposure of the embedded imbiber beads to water (with a resultant bead-swelling and sealing action), this sealing activity is greatly enhanced by the fact that the entire, adjacent and overlying coating structure is continually compressively influenced by the continuous “outer side” (water-side) pressure of water. In other words, and as was stated earlier, the very substance—water—whose leakage is to be prevented, is actually employed, through water-pressure compression of outer portions of the coating structure of the invention, to assist in sealing action.
These and other features and advantages that are offered by the present invention will become more fully apparent as the detailed description thereof which now follows is read in conjunction with the accompanying drawings.
The various structures which are illustrated in the drawing figures are not drawn to scale.